4,4-di-alkoxy-2,2,6,6-tetramethyl piperidines

ABSTRACT

4-Piperidone ketal derivatives of the formulae   WHEREIN R1 represents an alkyl group of 1 to 8 carbon atoms and R2 represents an alkylene group of 2 or 3 carbon atoms or ophenylene group and they are prepared by reacting triacetonamine with a monohydric alcohol of the formula

United States Patent [1 1 Murayama et al.

[ 51 Jan. 21,1975

l l 4,4-DI-ALKOXY-Z,2,6,6-TETRAMETHYL PIPERIDINES [75] Inventors:Keisuke Murayama; Toshimasa Toda; Eika Mori; Katsuaki Matsui; TomoyukiKurumada; Noriyuki Onta; lchiro Watanabe, all of Tokyo, Japan [73]Assignee: Sankyo Company Limited, Tokyo,

Japan 22 Filed: Mar. 1, 1973 21 Appl.No.: 336,982

Related US. Application Data [62] Division of Ser. No. 219,133, Jan. 19.1972, Pat. No.

FOREIGN PATENTS OR APPLICATIONS 660,763 8/1965 Belgium OTHERPUBLICATIONS CA. 61: 2364g (1964) Chod'era et al. CA. 68: 67,567n (1968)Chodera et al. CA. 59: 8750a (1963) Stach et al. CQA. 7th CollectiveIndex 19624966, page 17, 7285, Experientia 20: 437-438 (1964), Casy.

Primary Examiner-Henry R. Jiles Assistant Examiner-*8. D. WintersAttorney, Agent, or FirmToren and McGeady [57] ABSTRACT 4-Piperidoneketal derivatives of the formulae R 0 OR I1 0 CH H O N H R and H O CH HC N CH wherein R, represents an alkyl group of l to 8 carbon atoms and Rrepresents an alkylene group of 2 or 3 carbon atoms or o-phenylene groupand they are prepared by reacting triacetonamine with a monohydricalcohol of the formula R -OH (Ill) wherein R is as defined above or adihydric alcohol or phenol of the formula wherein R is as defined abovein the presence of an acid catalyst. They are useful as stabilizersagainst deterioration of synthetic polymers.

2 Claims, No Drawings and wherein R represents an alkyl group of l to 8carbon atoms and R represents an alkylene group of 2 or 3 carbon atomsor o-phenylene group, a process for the preparation of the 4-piperidoneketal derivatives (I) and (II) and stabilizationof synthetic polymersagainst photoand thermal-deterioration thereof by having incorporatedtherein, in a sufficient amount to prevent said deterioration, at leastone of the 4-piperidone ketal derivatives (I) and (II).

In the above formulae (I) and (II), R may be illustrated by methyl,ethyl, n-propyl, isopropyl, n-butyl, tert.butyl n-pentyl, isopentyl,hexyl, heptyl and octyl; and R may be illustrated by ethylene,trimethylene, propylene and o-phenylene.

The term synthetic polymer" as used herein are intended to embracepolyolefins including homopolymers of olefins such as low-density andhigh-density polyethylene, polypropylene, polystyrene, polybutadiene,polyisoprene and the like, and copolymers of olefins with otherethylenically unsaturated monomers such as ethylene-propylene copolymer,ethylene-butene copolymer, ethylene-vinyl acetate copolymer,styrene-butadiene copolymer, acrylonitrile-styrene butadiene copolymerand the like; polyvinyl chlorides and polyvinylidene chlorides includinghomopolymer of each of vinyl chloride and vinylidene chloride, vinylchloride-vinylidene chloride copolymer and copolymers of each of vinylchloride and vinylidene chloride with vinyl acetate or otherethylenically unsaturated monomers;

polyacetals such as polyoxymethylene and polyoxyethylene;

polyesters such as polyethylene terephthalate; polyamides such as6-nylon, 6,6-nylon and 6,l0-nylon; and polyurethanes.

Synthetic polymers have been widely utilized in the art, in view oftheir excellent properties, in various forms or shapes, for example,filament, fibre, yarn, film, sheet, other molded article, latex andfoam. However, these polymers have some drawbacks such as poor lightaandheat-stabilities and the like. Stated illustratively, polyolefins andpolyurethane elastomers frequently tend to undergo severe deteriorationwhen exposed to light such as sunlight or ultraviolet ray, and polyvinylchloride and polyvinylidene chloride frequently tend to deteriorate andbecome colored by the action of light and heat together with eliminationof hydrogen chloride therefrom. Polyamides are also frequently subjectedto photo-deterioration. For the purpose of stabilizing these syntheticpolymers against such deterioration, there have heretofore been proposedin the art a number of stabilizers; for example, for polyolefins,benzotriazole compounds and beamphenone compounds; for polyurethanes,phenol compounds and benzophenone compounds; and for polyvinyl chlorideand polyvinylidine chloride, lead salts such as basic lead silicate andtribasic lead maleate, and organotin compounds such as dibutyltinlaurate and dibutyltin maleate.

Although such prior stabilizers are known to be considerablysatisfactory, there still remained some problems to be improved.

Thus, numerous attempts have been made in the art to find and developnew and more effective stabilizers.

As a result of our extensive studies, it has now been found that the new4-piperidone ketal derivatives (I) and (II) of this invention can besatisfactorily prepared and exhibit a high stabilizing effect againstphoto-and thermal-deterioration of the synthetic polymers.

It is, accordingly, an object of this invention to provide new anduseful 4-piperidone ketal derivatives (I) and (II).

Another object is to provide a process for the preparation of thevaluable 4-piperidone ketal derivatives (I) and (II).

Still another object is to provide synthetic polymer compositionstabilized against the deterioration thereof by having incorporatedtherein a sufficient amount to prevent the deterioration of at least oneof the 4- piperidone ketal derivatives (I) and (II).

Other objects of this invention will become apparent to those skilled inthe art from the following descriptron.

In one aspect of this invention, the 4-piperidone ketal derivatives (I)and (II) are all new substances unknown in the art.

Representative of the 4-piperidone ketal derivatives of the aboveformulae (I) and (II) are as follows:

Compound No. Chemical Name l 4,4-diethoxy-2,2,6,6-tetramethylpiperidine.

2 4,4-di-n-butoxy-2,2,6,6-tetramethylpiperidine.

3 4,4-di-n-octoxy-2,2,6,6-tetramethylpiperidine.

4 l,4-dioxa-8-aza7,7,9,9-tetramethyl-spiro- [4.5 ldecane.

5 l,5-dioxa-9-aza-8,8,l0, l 0-tetramethyl-spiro- [5.5 lundecane 64,4-(o-phenylenedioxy)-2,2,6,6-tetramethylpiperidine.

wherein R, is as defined above or a dihydric alcohol or phenol havingthe formula wherein R is as defined above in the presence of an acidcatalyst.

In carrying out the process of this invention, the reaction can besuitably effected by intimately contacting triacetonamine with themonohydric alcohol (111) or the dihydric alcohol (IV) in the presence ofthe acid catalyst and, advantageously, under reflux in the presence of asuitable organic solvent. As the solvent may be advantageously employedany of inert waterimmiscible organic solvents that could not adverselyaffect the reaction, reactants and catalyst. Examples of the solventinclude aliphatic and aromatic hydrocarbons, e.g., n-hexane,cyclohexane, benzene, toluene and xylene.

The monohydric alcohol of the above formula (III) which may be employedin the reaction includes straight or branched monohydric alcohols, e.g.,methanol, ethanol, isopropanol and octanol. The dihydric alcohol orphenol of the above formula (IV) which may be employed in the reactionincludes, e.g., ethylene glycol, propylene glycol, trimethylene glycoland catechol. The acid catalyst which may be employed in the reaction isany of those catalysts commonly utilized in a standard condensationreaction with elimination of water and includes mineral acids, e.g.,hydrochloric acid and polyphosphoric acid; and organic acids, e.g.,methanesulfonic acid, benzensulfonic acid and p-toluenesulfonic acid,the organic acids being preferable.

As it is noted that the reaction of the present process be acondensation reaction accompanied with elimination of water, thereaction may be more smoothly and preferably effected with continuousremoval of the water that is being formed in situ during the reactionproceeding.

After completion of the reaction, the desired product may be readilyrecovered and purified in a conventional manner, for instance, by makingthe reaction mixture alkaline with an alkali hydroxide, separating anorganic layer followed by distillation under reduced pressure and, ifnecessary, recrystallization.

In still another aspect of this invention, there is provided a syntheticpolymer composition stabilized against photo-and thermal-deteriorationwhich contains at least one of the new 4-piperidone ketal derivatives(l) and (11) having incorporated therein.

The 4-piperidone ketal derivatives (I) and (11) employed as a stabilizerin the present invention may be readily incorporated into the syntheticpolymers by any of the various standard procedures commonly utilized inthe art. The stabilizer may be incorporated into the synthetic polymersat any desired stage prior to the manufacture of shaped articlestherefrom. Thus, for example, the stabilizer in the form of a dry powdermay be admixed with the synthetic polymer, or a suspension or emulstionof the stabilizer may be admixed with a solution, suspension or emulsionof the synthetic polymer.

The amount of the 4-piperidone ketal derivatives (I) and (II) employedin the synthetic polymer in accordance with the present invention may bevaried widely, depending upon the types, properties and particular usesof the synthetic polymer to be stabilized. In general, the 4-piperidoneketal derivatives of the formula (I) and (11) may be added in an amountranging from 0.01 to 5.0 percent by weight, based on the amount of thesynthetic polymer, but the practical range is varied depending upon thetype of the synthetic polymer, that is 0.01 to 2.0 percent by weight,preferably 0.02 to 1.0 percent by weight for polyolefins, 0.01 to 1.0percent by weight, preferably 0.02 to 0.5 percent by weight forpolyvinyl chloride and polyvinylidene chloride, and 0.01 to 5.0 percentby weight, preferably 0.02 to 2.0 percent by weight for polyurethanesand polyamides.

The present stabilizer may be used alone or in combination with otherknown antioxidants, ultraviolet absorbents, fillers, pigments and thelike.

If desired, two or more of the present stabilizers i.e. the 4-piperidoneketal derivatives of the formulae (1) and (11) may also besatisfactorily used in this invention.

In order that the invention may be better understood, the followingExamples are given solely for the purpose of illustration of thisinvention. In the Examples, all parts are given by weight unlessotherwise indicated and the number of the test compound as usedhereinbelow is the same as illustratively shown above.

Examples 1 through 4 describe the preparation of the 4-piperidone ketalderivatives.

Examples 5 through 9 describe the synthetic polymer compositions havingincorporated therein the 4- piperidone ketal derivatives and theirstablilization effects.

EXAMPLE 1 4,4-Di-n-butoxy-2,2,6,6-tetramethylpiperidine In a solution of23.4 g. of triacetonamine in ml. of benzene were added 23.2 g. ofn-butanol and 30 g. of p-toluenesulfonic acid. The resulting mixture washeated under reflux for 44 hours by means of a water separator.

Then, the reaction mixture was poured into a cold aqueous solution ofsodium hydroxide and the benzene layer was separated therefrom. Thelayer so separated was washed with water, dried over anhydrous sodiumsulfate and subjected to distillation under reduced pressure to give thedesired product as colorless liquids boiling at 123124C/4 mmHg. 1

IR (liquid film) v 1,093, 1,037 cm Analysis for C H NO Calculated: C,71.52%; H, 12.36%; N, 4.91%.

Found: C, 71.35%; H, 12.44%; N, 5.14%.

EXAMPLE 2 4,4-Di-n-octoxy-2,2,6,6-tetramethylpiperidine Thesubstantially same procedure as shown in the above Example 1 wasrepeated except that n-octanol was employed instead of the n-butanol,thereby yielding the desired product as colorless liquids boiling atl60l62C/0.45 mmHg.

IR (liquid film) 11 1092, 1038 cm Analysis for C H NO Calculated: C,78.67%; H, 13.47%; N, 3.67%.

Found: C, 78.41%; H, 13.15%; N, 3,85%.

EXAM PLE 3 1,4-Dioxa-8-aza-7 ,7 ,9,9-tetramethyl-spiro[4.5 ]decane Intoa solution of23.4 g. of triacetonamine in 150 ml. of benzene were added83 g. of ethylene glycol and 30 g. of p-toluenesulfonic acid and theresulting mixture was heated under reflux for 18 hours by means of awater separator.

Then, the reaction mixture treated in the same manner as shown in theabove Example 1 to give the desired product as colorless liquids boilingat 103.5l04.5C/3.4 mmHg.

IR (liquid film) v 1,091, 1,040 cm Analysis for C, I-I ,NO

Calculated: C, 66.29%; H, 10.62%; N, 7.03%.

Found: C, 66.39%, H, 10.74%, N, 6.98%.

Molecular weight (Osmometer);

Calculated: 119.29

Found: 205.7

EXAMPLE 4 4,4-(o-Phenylenedioxy)-2,2,6,6-tetramethylpiperidine Thesubstantially same procedure as shown in the above Example 3 wasrepeated except that catechol was employed instead of the ethyleneglycol to give the desired product as colorless liquids boiling at118-120C/3 mmHg.

Upon being allowed to cool, the liquids solidified and recrystallizationfrom aqueous methanol gave white crystals melting at 74 75C.

IR (Nujol mull) v 1,098, 1,064 cm Out-of-plane deformation absorption ofthe odisubstituted benzene ring 730-800 cm Analysis for C H NOCalculated: C, 72.84%; H, 8.56%; N, 5.66%.

Found: C, 72.73%; H, 8.71%, N, 5.90%.

EXAMPLE 5 Into 100 parts of polypropylene [Noblen JHH-G, trade name,available from Mitsui Toatsu Chemicals Inc., Japan, employed after twicerecrystallizations from monochlorobenzene] was incorporated 0.25 part ofeach of the test compounds of this invention indi cated below. Theresulting mixture was mixed and melted and then molded into a sheethaving a thickness of 0.5 mm. under heating and pressure.

As a control for comparative purpose, the polypropylene sheet wasprepared in a similar manner to that described above without any ofstabilizers.

Then, all of these sheets thus formed were tested for the brittlenesstime (which means the time, expressed in terms of hour, until the testsheet becomes brittle) under ultraviolet ray irradiation at atemperature of 45C by means of the fade meter prescribed in JapaneseIndustrial Standard JIS-l044 entitled Testing Method of Color Fastnessto Light of Dyed Textiles and Dyestuffs", Paragraph 3.8 (in English).

The results are given in the following Table 1.

Table 1 Test compound No. Brittleness time (hours) 2 620 3 860 4 960 61000 None 100 EXAMPLE 6 Into 100 parts of high-density polyethylene [Hi-5 Zex," trade name, available from Mitsui Toatsu Chemi- Table 2 Testcompound No. Brittleness time (hours) None 400 Example 7 Into parts of6-nylon [CM 1011,? trade name, available from Toray Industries Inc.,Japan, containing no stabilizer] was incorporated 0.25 part of each ofthe test compounds of this invention indicated below. The resultingmixture was heated and melted and then molded into a film having athickness of about 0.1 mm. under pressure by a conventional compressionmolding machine. The film thus formed was aged under the following agingcondition and thereafter subjected to a tensile test to determine theretentions of tensile strength and elongation by a standard method.

Aging test 1. Exposure to ultraviolet ray for 300 hours in the fademeter described above at 45C.

2. Aging at C for 2 hours in a Geers aging tester prescribed in JapaneseIndustrial Standard JIS-K- 6301 entitled Physical Testing Methods forVulcanized Rubber," Paragraph 6.5 (in English).

The results are given in the following Table 3.

Into 100 parts of polyurethane prepared from polycaprolactone [E-5080,trade name, available from The Nippon Elastollan Industries Ltd., Japan]was incorporated 0.5 part of each of the test compounds of thisinvention indicated below. The resulting mixture was heated and meltedand then molded into a sheet having a thickness of about 0.5 mm. Thesheet thus formed was subjected to the exposure to ultraviolet ray for15 7 8 hours in the fademeter as specified in the above Exam- Geersaging tester prescribed in the above Example ple at 45C and then testedfor the retentions of elon- 7. The results are given in the followingTable 5. gation and tensile strength as in the above Example 7. l

Table 5 The results are glven m the following Table 4.

Table 4 5 Discoloration Test compound Sunshine carbon Geer's agingtester Test compound Retention of Retention of tensile NO- pp r te 90tes.

No. elongation strength (after 600 hours) l70C) 2 85 92 2 Pale yellowYellow 4 38 89 4 Pale yellow Pale yellow 6 95 94 6 Slightly yellowishSlightly yellowish None 75 53 None Dark brown Black EXAMPLE 9 From theabove results it can be seen that the 4- piperidone ketal derivatives ofthis invention exhibit a high,

Into 100 parts of polyvinyl chloride [Geon 103 EP, trade name, availablefrom The Japanese Geon Co., Ltd., Japan] were incorporated 1.0 part oflead stearate, 0.5 part of dibasic lead phosphite, 0.5 part of bariumstearate, 0.5 part of cadmium stearate and 0.2 part of each of the testcompounds of this invention indi- R 0 OR cated below. The resultingmixture was blended and 1 kneaded for 4 minutes on a kneading roll toform a sheet having a thickness of 0.5 mm. The sheet was degree ofstabilizing effect on synthetic polymers against deteriorations thereof.

What is claimed is: 1. A compound having the formula tested for thediscoloration degree thereof by the aging 5 5 test method set forthbelow. H C CH Aging test 3 H g 5 1. Exposure for 600 hours to thesunshine carbon apparatus prescribed in Japanese Industrial Standard JISwherein 1 represents an alkyl g p of 1 t0 3 Carbon 2-0230 entitledAccelerated Weathering Test of O atoms. Rust Proofing Oils, Paragraph 2.2. 4,4-Di-n-butoxy-2,2,6,-tetramethylpiperidine.

2. The sheet was aged for 90 minutes at 170C in the

2. 4,4-Di-n-butoxy-2,2,6,6-tetramethylpiperidine.